Firefighting is a highly dangerous occupation that subjects firefighters to many hazards. It is critically important that firefighters have the right amount of water flow (gallons per minute or gpm) when they are combating a fire in various conditions and environments. Determining the water flow rate in a fire hose is an important task for firefighters responsible for operating fire apparatus pumps. Delivering water at the proper flow rate and pressure to firefighters controlling the fire hose nozzles is vital to ensure safe operations. Pressures and flow rates too low will be insufficient for fire control, while pressures and flow rates that are too high creates dangerous conditions with handling the nozzle, burst hose, and other hazards.
Presently there are electric devices for controlling opening and closing discharge valves on a firefighting vehicle, such as a tanker or pumper fire engine. These electric control devices operate at fixed speeds to open or close the valve. When a firefighter desires to make small adjustments of the discharge valve to change the flow rate from 100 gpm to 105 or 110 gpm, for example, it is very easy to overshoot the desired setting, and multiple manipulations of the controls are often required to reach the desired flow rate.